Hairstyling Apparatus Using Steam with Steam-Confining Means

ABSTRACT

Provided is a hairstyling apparatus (I) including a portable treatment unit ( 2 ) provided with two arms ( 3, 4 ) arranged to form a clamp provided with two surfaces ( 5, 6 ) disposed opposite one another and enabling a lock of hair to be clamped therebetween. The portable treatment unit includes steam-diffusion means ( 7 ) arranged to diffuse steam from a first ( 5 ) of the two surfaces towards the second ( 6 ) of the two surfaces. The apparatus includes means ( 9, 10 ) for confining the diffused steam, between the two surfaces (5, 6) placed one against the other.

The invention concerns a hairstyling apparatus using steam that comprises a handheld steam treatment unit intended to treat hair with steam in order to style it. In addition to steaming hair, the handheld treatment unit of this hairstyling apparatus is generally configured to heat hair in order to style it. For example, such a hairstyling apparatus, depending on its configuration, can be used to straighten, curl, or crimp hair.

Various hairstyling apparatuses are known that can be used to treat hair in order to straighten, curl, or crimp it. These hairstyling apparatuses comprise a handheld treatment unit consisting primarily of two arms, or jaws, each with a surface that can be flat or curved. The two arms have a joint between them so as to form a clamp configured to grip hair between the two surfaces that face each other, when the two arms come together. These two arms also include an area to which gripping pressure is applied in order to open and close the clamp and manipulate it during styling. At least one of these two surfaces has a heating device so that hair can be heated while clamped. A lock of hair is straightened by clamping the lock between the two surfaces and moving the closed clamp along the lock, from the root toward the end. A lock of hair is curled by clamping the lock between the two surfaces and rolling the lock at least partially around the surfaces, with heat making the hair hold the curl.

To improve hairstyling, it is known to use steam treatment in addition to the heat treatment, with the steam projected or diffused onto the hair. Several examples of embodiments of such hairstyling apparatuses are described in documents JP2000157322A, EP1396207A1, EP1515628B1, EP1515629B1, EP1516554B1, FR2967017A1. According to these various embodiments, in addition to the known and aforementioned characteristics of a hairstyling apparatus, the handheld treatment unit includes a means of projecting steam configured to project the steam from the first of the two surfaces to the second of the two surfaces. In documents EP1396207A1 and EP1516554B1, the handheld treatment unit includes a means of aspirating the steam, located on said second surface, to evacuate the steam projected from the first surface after it passes through the lock of hair. In documents EP1515628B1 and EP1515629B1, in one possible embodiment, the means of projecting steam are configured to project the steam from the two surfaces that face each other during clamping. In document FR2967017A1, a patent application filed by the applicant, the optimized design of the steam generation means allows for a steam flow rate on the order of 3-4 g/min., higher than other hairstyling apparatus designs that offer a steam flow rate of less than 2 g/min., which makes it possible to supply steam evenly to the entire length of the clamped lock of hair during steam treatment and allows that lock of hair to be rapidly steam treated as the handheld treatment unit is moved along the lock of hair.

This invention is intended to provide a hairstyling apparatus with performance comparable to that of the hairstyling apparatus described in document FR2967017A1 while reducing its size, for example reducing the length of the hairstyling apparatus and/or the height, for example.

This invention is intended to provide a hairstyling apparatus with performance comparable to that of the hairstyling apparatus described in document FR2967017A1, but using a lower steam flow rate.

This invention is intended to provide a hairstyling apparatus with performance comparable to that of the hairstyling apparatus described in document FR2967017A1 while simplifying its design.

This invention is intended to provide a hairstyling apparatus with performance comparable to that of the hairstyling apparatus described in document FR2967017A1 while decreasing its manufacturing cost.

This invention is intended to provide a hairstyling apparatus with performance comparable to that of the hairstyling apparatus described in document FR2967017A1 while reducing the volume of liquid used for steam generation.

Accordingly, the invention concerns a hairstyling apparatus comprising a handheld treatment unit having two arms configured to form a clamp with two surfaces that face each other, together allowing a lock of hair to be clamped. The handheld treatment unit includes a means of diffusing steam configured to diffuse steam from the first of the two surfaces toward the second of the two surfaces. It is noteworthy that the hairstyling apparatus includes a means of confining the diffused steam between the two surfaces clamped against each other. This means of confinement makes it possible to keep a quantity of steam in contact with the lock of hair, with even distribution, in a confinement space located between the two surfaces that are clamping the lock of hair, to provide optimal steam treatment. This steam remains in the confinement space for a length of time before escaping under the steam flow action. This steam confinement allows the advantage of reducing the steam flow from the means of steam generation in the handheld treatment unit. The steam is provided and circulates by diffusion or projection means, and circulates with or without excessive pressure.

According to the invented hairstyling apparatus, the means of steam confinement comprises a groove located in the second of the two surfaces, facing the means of diffusion. The steam passes through the lock of hair and remains confined in that groove.

According to this embodiment of the invented hairstyling apparatus, the groove opens onto at least one of the two longitudinal edges of the second surface, so as to allow this steam to escape under the action of the steam flow exiting the means of diffusion, after having kept that steam confined in said groove. The steam in the confinement space is thereby renewed. This makes it possible to maintain a level of steam pressure in the confinement space that can be essentially constant.

According to this embodiment of the invented hairstyling apparatus, the groove is between 2 and 6 mm wide, preferably 2.5 mm, and between 0.5 and 2 mm deep, preferably 1 mm. These dimensions allow the confinement space to be optimized so as to maintain a sufficient amount of renewed steam in contact across the width of a lock of hair in order to style it. In addition, the groove is between 20 and 220 mm long, preferably 90 mm, so as to optimize the volume of the confinement space for a lower steam flow rate of 0.5 to 2 g/min., preferably between 0.9 and 1.2 g/min.

According to the invented hairstyling apparatus, the first surface contains a furrow with a bottom surface, wherein the means of steam diffusion is placed so as to diffuse the steam from that bottom surface, and the means of steam confinement comprises the furrow, in addition to or even in substitution of the aforementioned groove located in the second of the two surfaces.

When the invented hairstyling apparatus includes both a groove and a furrow as described above, the groove is located facing the furrow. In addition, the groove and the furrow preferably have essentially identical volumes.

In one variation of the invented hairstyling apparatus, having a groove as described above, the first surface has two adjoining furrows, each with a bottom surface, and the means of diffusion are placed so as to diffuse the steam from at least one of those two bottom surfaces. In addition, the groove is placed so as to face the two furrows.

According to the invented hairstyling apparatus, at least one furrow opens onto at least one of the two longitudinal edges of the first surface, which allows steam to escape after having been diffused and held in the confinement space.

In one embodiment of the invented hairstyling apparatus, the means of steam diffusion includes multiple diffusion orifices located along the bottom surface of at least one furrow. In one variation, this means of steam diffusion includes a diffusion slot located on the bottom surface of at least one furrow.

According to one embodiment of the invented hairstyling apparatus, there is a grid above the at least one furrow on the first surface. This contributes to better distribution of the steam onto the lock of hair.

According to another embodiment of the invented hairstyling apparatus, it has a single furrow with a curved shape. In addition, the groove has a rounded grid whose form matches said curved furrow. This contributes to better distribution of the steam onto the lock of hair while keeping it under tension as the handheld treatment unit holding the lock of hair is moved.

According to another embodiment of the invented hairstyling apparatus, it has a furrow and a groove that are circular in shape, so as to form a cylinder when the clamp is in closed position. In addition, the hairstyling apparatus includes a perforated roller mounted so as to rotate inside of that cylinder. This allows steam to be distributed into the confinement space constituted by said cylinder, with the rotation of the roller preventing the lock of hair from being pulled as the handheld treatment unit is moved along the lock of hair.

According to the invented hairstyling apparatus, the means of steam confinement are off-center on the surfaces. It must be understood that the means of confinement are not in the middle of the surfaces but rather upstream or downstream on the surfaces. More precisely, the means of confinement can be in the form of a confinement system that is off-center on the treatment surface, for example a single assembly formed at least by the groove that is off-center on the treatment surface or straightening plate with respect to its median plane and crosses it orthogonally.

According to the invented hairstyling apparatus, each of the two surfaces has a heating plate, and those heating plates are located facing each other and together can clamp a lock of hair. This allows heat treatment of the lock of hair at the same time as steam treatment.

Preferably, according to this embodiment of the hairstyling apparatus with two heating plates, the means of steam confinement are located between the two heating plates. This offers the advantage of heating the steam that is present in the confinement space.

According to this preferred embodiment of the invented hairstyling apparatus, the means of steam confinement are off-center on the downstream parts of the heating plates, which allows the lock of hair to be steam-treated before it is heat-treated, as the handheld treatment unit is moved along the lock of hair. Preferably, the median line of the means of confinement is located at a distance d1 from the downstream edge of the heating plates, and the ratio of the distance d1 to the width l1 of the heating plates is between 0.1 and 0.4.

According to the invented hairstyling apparatus, a comb is located downstream of one of the surfaces. This makes it possible to untangle and aerate the lock of hair before it is steam-treated, thus promoting the passage of steam through the hair.

According to the invented hairstyling apparatus, it includes a steam shut-off that is configured to block the steam escaping from the means of confinement in the direction of the proximal part of the clamp, with said proximal part configured for manipulating the handheld treatment unit. This protects the hand that is manipulating the handheld treatment unit against steam burns.

According to the invented hairstyling apparatus, the means of steam diffusion are configured so as to deliver a steam flow rate between 0.5 g/min. and 2 g/min., preferably between 0.9 g/min. and 1.2 g/min. This allows the use of traditional or innovative means of steam generation on the handheld treatment unit, with a limited size and a simplified design compared to those described in document FR2967017A1.

The following description of various embodiments shows the characteristics and advantages of the invented hairstyling apparatus. This description is based on figures, which include:

FIG. 1 illustrates an invented hairstyling apparatus, of the steam straightener type;

FIGS. 2 and 3 illustrate two heating plates located on the two arms of the handheld treatment unit, respectively in the clamped and open positions of the clamp;

FIG. 4 illustrates an invented hairstyling apparatus, showing the presence of a steam shutoff;

FIG. 5 illustrates a heating plate with two adjoining furrows having means of steam diffusion;

FIG. 6 illustrates a heating plate with a furrow having a perforated grid;

FIG. 7 illustrates two heating plates in clamped position and shows a curved shape of the furrow and a rounded perforated grid covering the groove;

FIG. 8 illustrates two heating plates in clamped position and shows a cylindrical shape constituted by the furrow and the groove, with a perforated roller in the cylinder;

FIGS. 9, 10, 11, and 12 illustrate other alternatives for executing the means of confinement.

In the following description, the same references are used to designate identical or similar characteristics according to the various embodiments of the invented hairstyling apparatus that are described with reference to FIGS. 1-12.

In FIG. 1, the invented hairstyling apparatus 1 is a hair straightener. It comprises a handheld treatment unit 2. This handheld treatment unit 2 is powered electrically by means of an electrical cord 8. The handheld treatment unit 2 comprises two arms 3, 4—also called jaws—joined to each other by means of a pivot connection 21 that enables them to clamp.

Each of the two arms 3, 4 has a proximal part 3 a, 4 a. These two proximal parts 3 a, 4 a can be gripped simultaneously with one hand, permitting manipulation of the handheld treatment unit 2 and closing of the clamp when the two proximal parts 3 a, 4 a are squeezed together.

The two arms 3, 4 each have a surface 5, 6 on the internal face of their distal part 3 b, 4 b that together allow the lock of hair to be clamped. According to the embodiment in FIG. 1, the surfaces 5, 6 are flat, forming two heating plates 17, 18. When the clamp is closed, the heating plates 17, 18, which face each other, come into contact with each other, resulting in the clamping action.

In one embodiment, the handheld treatment unit 2 of the hairstyling apparatus 1 according to the invention will be able to duplicate technical characteristics similar to those described in patent application FR2967017A1 filed by the applicant, regarding implementation of the means of heating (not shown) for the heating plates 17, 18. In this regard, the means of heating for the heating plates 17, 18 each have a heating device (not shown) consisting of a thermal resistor with a positive temperature coefficient, or PTC, and a device (not shown) for measuring the temperature of the heating device consisting of a thermal resistor with a negative temperature coefficient, or NTC. These heating and measurement devices will be located in housing zones 22, 23 on each arm 3, 4 for each of the heating plates 17, 18. Since the characteristics of such means of heating the heating plates 17, 18 are known to professionals in this field, they will not be described further. Variations that are known to professionals in this field or innovative are equally possible for these means of heating the heating plates 17, 18 without going beyond the scope of the invention. In addition, variations in shape are possible for the surfaces 5, 6. In particular, curved surfaces can be implemented, such as those found on hairstyling apparatuses used to curl hair, or even wavy surfaces, such as those found on hairstyling apparatuses used to crimp hair. In addition, embodiments of the handheld treatment unit 2 are possible with only one of the two surfaces 5 or 6 emitting heat, and the other surface merely contributing to clamping the lock of hair in order to style it.

The handheld treatment unit 2 of the hairstyling apparatus 1 also comprises means of projecting or diffusing steam 7 from the first surface 5 toward the second surface 6. As shown in FIGS. 1-3, the first arm 3 has a furrow 10 with a bottom surface 11 in which orifices 12 are located that allow the projection or diffusion of steam toward the second arm 4 when the clamp is closed. The first arm 3 also has, at its distal part 3 b, a steam generation chamber (not shown) that allows steam to be generated and projected or diffused through the orifices 12. In one embodiment, the handheld treatment unit 2 of the hairstyling apparatus 1 according to the invention will be able to duplicate technical characteristics comparable to those described in patent application FR 2 967 017 A1 filed by the applicant, regarding implementation of the steam generation chamber. Accordingly, this steam generation chamber comprises in particular a heating device (not shown) consisting of a thermal resistor with a positive temperature coefficient, or PTC, and a device (not shown) for measuring the temperature of the heating device consisting of a thermal resistor with a negative temperature coefficient, or NTC. These heating and measurement devices are located in a second housing zone 24 shown in FIG. 2, under the first housing zone 22. Variations that are known to professionals in this field or innovative are equally possible for this steam generation chamber, without going beyond the scope of the invention. Preferably, eight orifices 12 with a diameter of 1.2 mm are located in the bottom surface 11 of the furrow 10. In addition, the means of steam projection or diffusion are configured so as to project or diffuse steam at a flow rate between 0.5 g/min. and 2 g/min., preferably between 0.9 g/min. and 1.2 g/min. Professionals in the field are able to configure such means of steam projection or diffusion so as to obtain such a flow rate. However, a flow rate between 0.5 g/min. and 5 g/min., essentially equal to 4 g/min., for example, is possible for a hairstyling apparatus that is smaller than that described in document FR2967017A1 and capable of producing the same flow rate.

Other characteristics, also known to professionals in the field, are also implemented on the hairstyling apparatus 1 according to the invention. The handheld treatment unit 2 comprises, in particular, a circuit board (not shown) that is configured to manage the activation of the two heating plates 17, 18 and the steam generation chamber. This circuit board is located inside one of the two arms 3, 4, in the proximal part 3 a of the first arm 3, for example. The handheld treatment unit 2 comprises a magnetic sensor 25, shown in FIG. 1, of the reed switch (RS) type, which is able to detect the closed position of the clamp when the two surfaces 5, 6 close against each other and clamp a lock of hair. In one variation, the reed switch could be replaced by a magneto-resistive sensor, or MRS.

As illustrated in FIGS. 1-3, the furrow 10 is located in the downstream part 17 a of the first heating plate 17 (or first surface 5 which is not necessarily a heating surface), relative to the movement direction of the handheld treatment unit 2 from the root to the end of the hair, as indicated by the arrow 26 in FIG. 2. This makes it possible to steam-treat the lock of hair before it is heat-treated (respectively, or not necessarily heated when clamped). The two ends of the furrow 10 preferably open onto the longitudinal edges 5 a, 5 b of the first surface 5. However, a variation is also possible in which the furrow 10 opens only onto one of the longitudinal edges 5 a, 5 b. As shown in FIG. 2, the median line 27 of the furrow 10 is located at a distance d1 from the downstream lateral edge 29 of the first heating plate. The ratio of this distance d1 to the width l1 of this heating plate 17 is preferably between 0.1 and 0.4. For example, the width of the plate is equal to 28.9 mm and the distance d1 is equal to 6.25 mm, corresponding to a ratio of 0.22.

As shown in FIGS. 1-3, a groove 9 is located in the downstream part 18 a of the second heating plate 18, facing the furrow 10. According to this embodiment, the groove 9 and the furrow 10 are of essentially identical shape and volume. The groove or the groove and furrow assembly forms a means of confining the diffused steam. As with the furrow 10, both ends of the groove 9 open onto the longitudinal edges 6 a, 6 b of the second surface 6. The groove 9 and the furrow 10 are dimensioned so as to concomitantly constitute a confinement space 28 for the steam flowing out of the orifices 12. This confinement space 28 makes it possible to contain the steam around the lock of hair clamped between the two surfaces 5, 6, before allowing that steam to escape through the ends of the groove 9 and the furrow 10, due to the replacement steam flowing from the orifices 12. Confining the steam enhances the steam treatment of the lock of hair while using a lower rate of steam flow, preferably between 0.9 g/min. and 1.2 g/min., while ensuring fairly rapid movement of the handheld treatment unit 2 along the lock of hair. In addition, having the confinement space 28 between the two heating plates 17, 18 allows for advantageous reheating of the steam confined in that space. In order to have this confinement space 28, the furrow 10 should preferably be between 2 mm and 6 mm wide, preferably 2.5 mm, and the furrow 10 should be between 0.5 mm and 2 mm deep, preferably 1 mm. In addition, the volume of the furrow 10 should preferably be between 200 mm³ and 275 mm³, preferably 225 mm³. The furrow 10 should preferably be between 20 mm and 220 mm long, preferably 90 mm. The dimensions and volume of the groove 9 should preferably be similar, which allows the confinement space 28 to have a volume between 400 mm³ and 550 mm³, preferably 450 mm³.

As shown in FIG. 4, the handheld treatment unit 2 comprises a steam shutoff 20 located on the first arm 3, on the proximal longitudinal edge 5 a of the first surface 5. This steam shutoff 20 prevents the steam that is escaping from the confinement space 28 from entering the area where the handheld treatment unit 2 is gripped, consisting of the proximal parts 3 a, 4 a of the two arms 3, 4.

FIG. 5 illustrates one variation of the means for projecting or diffusing steam 7 onto the first surface 5. These means of projecting or diffusing steam 7 include two adjoining furrows 10, 10′ with a design similar to that illustrated in FIGS. 1-3, located on the downstream part 17 a of the first heating plate 17. Each furrow 10, 10′ includes orifices 12, 12′ located on the bottom surface 11, 11′ of said furrow 10, 10′, through which steam is projected, diffused, and transported. According to this implementation example, the groove 9 located on the second heating plate 18 has a width that matches the total width of the two furrows 10, 10′. The steam flow rate is also between 0.5 g/min. and 2 g/min., preferably between 0.9 g/min. and 1.2 g/min. The volume of the confinement space in this case is constituted by the volumes of the groove 9 and the furrows 10, 10′. This volume falls within a range of values that are twice that of the volume of the confinement space 28 in the embodiment shown in FIGS. 1-3. In effect, the steam channel or groove is doubled compared to the preceding embodiments, so that the steam follows a double channel and the lock of hair is steam-treated twice. The channels can be circulating fluid to one end of the surface(s). In this configuration, where steam is circulated from parallel channels through one channel to form a U shape, one alternative is for the steam outlet orifices to be present in only one of the channels (not shown).

In FIG. 6 the means for projecting or diffusing steam 7 are similar to those in FIGS. 1-3. In addition, a grid 13 is placed over the furrow 10, which promotes even distribution of the steam being produced and moved, in the confinement space 28 comparable to that shown in FIGS. 1-3. Such a grid 13 can be placed on each furrow 10, 10′ in the embodiment shown in FIG. 5.

In the embodiment from FIG. 7, the furrow 10 has a curved shape. The groove 9 includes a rounded grid 14 whose form complements that of said curved furrow 10. This rounded grid allows steam to be distributed evenly into the confinement space 28, and the lock of hair to be pulled as the handheld treatment unit 2 is moved. The volume of the confinement space 28 falls within a range of values similar to that of the embodiment shown in FIGS. 1-3.

In FIG. 8, the furrow 10 and the groove 9 are circular in shape and define a cylinder 15 when the clamp is closed, with said cylinder 15 defining the confinement space 28. In addition, a perforated roller 16 is located and rotates around an axis X inside of the cylinder 15. This perforated roller 16 can be powered. The volume of the cylinder 15 falls within a range of values similar to that for the volume of the confinement space 28 from the embodiment shown in FIGS. 1-3.

Each of FIGS. 9, 10, 11, and 12 illustrates other alternatives for executing the means of confinement from FIG. 2, but they can be implemented in any of the ways described, alone or in combinations. The common point of these alternatives is one or two special piece(s) labeled 30, 30 a, one or both of which are inserted into one or two spaces (hereinafter called gutters) provided in one or both of the heating plates. Such a piece inserted into the plate at least partially defines the contour of the means of confinement. This or these pieces make it possible to introduce additional functions to the treatment with confined steam.

Accordingly, FIG. 9 illustrates one spacing configuration with one or two glass pieces inserted respectively into a provided space that is larger than the space in the groove at the end of the heating plates. One or more groove(s) are formed in one or both glass pieces. The glass piece(s) can be illuminated by one or more light-emitting diodes (LEDs) to form light bars on each side of the confinement groove.

FIG. 10 illustrates an alternative in which the steam is carried by two channels 31, 31 a that carry steam coming from the steam generation chamber. For this, the special piece is inserted into the larger space provided on the treatment surface of the plates. This piece makes it possible to redirect the steam coming through the channel from the steam generation chamber.

FIG. 11 illustrates an alternative in which the special piece(s) are made of aluminum, for example, and painted, and slide into the space provided, for example. They can be secured by dovetailing. It is possible to change the size of the groove(s) by replacing one or both of the special pieces.

Finally, FIG. 12 illustrates an alternative in which the special piece(s) 30, 30 a are made of silicone. Advantageously and as shown, the silicone piece 30, 30 a, when in place, can project from the surface of the heating plate 17 and thereby create a hair tension zone 32 or traction zone 32 next to the groove, allowing for better straightening that is more gentle to the lock of hair.

In FIG. 1, a comb 19 is located downstream of the first surface 5 on the first arm 3. This comb 19 makes it possible to untangle and aerate the lock of hair before it passes between the two surfaces 5, 6.

Other implementation variations are possible within the scope of the invention. In particular, a confinement space can be provided that is constituted only by the volume of a groove 9 in the second surface 6, or only by the volume of a furrow 10 comprising orifices 12 for diffusing or projecting steam, on the first surface 5. In this case, said volume of the groove 9 or the furrow 10 should be dimensioned so as to constitute said steam confinement.

The means of confinement and the means of diffusing or projecting the steam 7 can also be placed on the surfaces 5, 6, separate from the heating plates 17, 18, with said means of confinement and means of diffusing or projecting the steam 7 located downstream of said heating plates 17, 18.

According to the various aforementioned embodiments, it is also possible to replace the orifices 12 for diffusing or projecting steam through a steam diffusion or projection slot located in the bottom surface 11, 11′ of the furrow 10, 10′, maintaining a steam flow rate between 0.5 g/min. and 2 g/min., preferably between 0.9 g/min. and 1.2 g/min.

According to the various aforementioned embodiments, it is possible to add an onboard ionizer, used to deliver ions into the means of steam confinement in order to eliminate static electricity. 

1. Hairstyling apparatus comprising a handheld treatment unit having two arms configured to form a clamp with two surfaces that face each other, together allowing a lock of hair to be clamped, wherein the handheld treatment unit comprises means of diffusing steam configured to diffuse steam from a first of the two surfaces to the second of the two surfaces, wherein the apparatus comprises means of confining the diffused steam, between the two surfaces pressed against each other.
 2. Hairstyling apparatus as in claim 1, in which a comb is located downstream of one of the surfaces.
 3. Hairstyling apparatus as in claim 1, in which each of the two surfaces has a heating plate, and wherein the heating plates are located facing each other and together can clamp a lock of hair.
 4. Hairstyling apparatus as in claim 1, in which the means of steam confinement is located between the two heating plates.
 5. Hairstyling apparatus as in claim 1, in which the means of steam confinement includes a groove located in the second of the two surfaces, facing the means of diffusion.
 6. Hairstyling apparatus as in claim 5, in which the groove opens onto at least one of two longitudinal edges of the second surface.
 7. Hairstyling apparatus as in claim 5, in which the groove is between 2 and 6 mm wide.
 8. Hairstyling apparatus as in claim 5, in which the groove is between 20 and 220 mm long.
 9. Hairstyling apparatus as in claim 5, in which the first surface contains a furrow with a bottom surface, wherein the means of diffusing steam is placed so as to diffuse the steam from the bottom surface, and the means of steam confinement comprises the furrow.
 10. Hairstyling apparatus as in claim 9, in which the groove is located facing the furrow.
 11. Hairstyling apparatus as in claim 10, in which the groove and the furrow have essentially identical volumes.
 12. Hairstyling apparatus as in claim 5, in which the first surface has two adjoining furrows each with a bottom surface, wherein the means of diffusing steam is placed so as to diffuse the steam from at least one of said two bottom surfaces, and wherein the groove is located facing the two furrows.
 13. Hairstyling apparatus as in claim 9, in which at least one furrow opens onto at least one of two longitudinal edges of the first surface.
 14. Hairstyling apparatus as in claim 13, in which the means of diffusing steam includes multiple diffusion orifices located along the bottom surface of at least one furrow.
 15. Hairstyling apparatus as in claim 9, in which the means of diffusing steam includes a diffusion slot running lengthwise along the bottom surface of at least one furrow.
 16. Hairstyling apparatus as in claim 9, in which a grid is located above the at least one furrow of the first surface.
 17. Hairstyling apparatus as in claim 9, in which the furrow has a curved shape and the groove includes a raised grid whose shape complements that of said curved furrow.
 18. Hairstyling apparatus as in claim 9, in which the furrow and the groove have a circular shape so as to form a cylinder in the closed position of the clamp, with said apparatus having a perforated roller mounted so as to rotate inside said cylinder.
 19. Hairstyling apparatus as in claim 1, in which the means of steam confinement is located off-center on the two surfaces.
 20. Hairstyling apparatus as in claim 4, in which the means of steam confinement is placed off-center on downstream parts located on the first and second heating plates.
 21. Hairstyling apparatus as in claim 20, in which a median line of the confinement means is located at a distance d1 from the downstream edge of the heating plates, and a ratio of the distance d1 to a width l1 of the heating plates is between 0.1 and 0.4.
 22. Hairstyling apparatus as in claim 1, which includes a steam shut-off configured to block the steam escaping from the means of confinement in the direction of a proximal part of the clamp which is configured for manipulating the handheld treatment unit.
 23. Hairstyling apparatus as in claim 1, in which the means of diffusing steam is configured so as to deliver a steam flow rate between 0.5 g/min. and 2 g/min.
 24. Hairstyling apparatus as in claim 5, in which the means of diffusing steam defines a confinement space measured by a volume of the groove in the second surface.
 25. Hairstyling apparatus as in claim 9, in which the means of diffusing steam defines a confinement space measured by a volume of the furrow comprising steam diffusion orifices in the first surface. 